As the demand increases for varying types of applications within mobile telecommunications networks, service providers must constantly upgrade their systems in order to reliably provide this expanded functionality. What was once a system designed simply for voice communication has grown into an all-purpose network access point, providing access to a myriad of applications including text messaging, multimedia streaming, and general Internet access. In order to support such applications, providers have built new networks on top of their existing voice networks, leading to a less-than-elegant solution. As seen in second and third generation networks, voice services must be carried over dedicated voice channels and directed toward a circuit-switched core, while other service communications are transmitted according to the Internet Protocol (IP) and directed toward a different, packet-switched core. This led to unique problems regarding application provision, metering and charging, and quality of experience (QoE) assurance.
In an effort to simplify the dual core approach of the second and third generations, the 3rd Generation Partnership Project (3GPP) has recommended a new network scheme it terms “Long Term Evolution” (LTE). In an LTE network, all communications are carried over an IP channel from user equipment (UE) to an all-IP core called the Evolved Packet Core (EPC). The EPC then provides gateway access to other networks while ensuring an acceptable QoE and charging a subscriber for their particular network activity.
The 3GPP generally describes the components of the EPC and their interactions with each other in a number of technical specifications. Specifically, 3GPP TS 29.212, 3GPP TS 29.213, and 3GPP TS 29.214 describe the Policy and Charging Rules Function (PCRF), Policy and Charging Enforcement Function (PCEF), and Bearer Binding and Event Reporting Function (BBERF) of the EPC. These specifications further provide some guidance as to how these elements interact in order to provide reliable data services and charge subscribers for use thereof.
The 3GPP specifications further describe methods of data plane traffic propagation. Data plane traffic is to be carried from the user equipment to the packet data network via virtual connections called “service data flows (SDFs).” Each SDF is to be carried by a virtual container called a “bearer.” Each bearer is associated with specific quality of service (QoS) characteristics and may carry multiple SDFs. Thus, particular QoS settings may be assured for an SDF by associating the SDF with a matching bearer.
As described by 3GPP TS 29.212, 3GPP TS 29.213, and 3GPP TS 29.214, SDFs may be established in various manners. For example, SDFs may be established at the request of an Application Function (AF) associated with the provider of a service associated with the requested SDF. Such requests may be referred to as “network-initiated” requests. SDFs may also be established at the request of user equipment (UE). These requests may arrive at the PCRF from the Serving Gateway (SGW) or Packet Data Network Gateway (PGW) and are referred to as “UE-initiated” requests. In some situations a request for an SDF may involve multiple messages, originating from both an AF and a UE.
Depending on factors such as the equipment serving a particular SDF, the EPC may not be able to fulfill all types of SDF requests. For example, in some implementations, network-initiated requests may not be allowed. 3GPP TS 29.212 describe a setting called “bearer control mode” which indicates what requests should be processed for a particular IP-CAN session. Bearer control mode may be set to a value of “UE_ONLY,” indicating that the UE must request any resource establishment, modification, or termination; or “UE_NW,” indicating that both network-initiated and UE-initiated requests are to be fulfilled.
The 3GPP specifications do not, however, describe how the PCRF should determine which bearer control mode setting is appropriate for a given IP-CAN session. The 3GPP specifications also fail to describe how the PCRF should identify and handle a situation where the bearer control mode should be changed. Without these steps, it becomes difficult for the EPC to provide reliable resource allocations that adapt to the needs of a mobile device and serving hardware.
In view of the foregoing, it would be desirable to provide a method for handling resource allocation requests. In particular, it would be desirable to provide a PCRF that may flexibly respond to resource allocation requests requiring an assessment of the bearer control mode for an SDF associated with the request. It would further be desirable to provide a PCRF that can handle a change to a bearer control mode associated with an SDF without introducing undesirable effects or violating any relevant specifications.